The sphincter of Oddi is located at the confluence of the bile duct, the pancreatic duct, and the duodenum, where it regulates the flow of bile and pancreatic juices into the small intestine, typically following the ingestion of a meal. Both biliary and pancreatic sphincters are part of the sphincter of Oddi, which is subject to a medical condition known as Sphincter of Oddi Dysfunction (SOD), a motility disorder. SOD can manifest itself as various problems within the bile or pancreatic ducts, such as formation of gallstones that obstruct the biliary duct, pancreatitis resulting from retrograde bile flow into the pancreatic duct, or post-cholecystectomy pain. Sphincter of Oddi Dysfunction has been found to be a leading cause of recurrent pancreatitis. Diagnosis of SOD can be performed by an endoscopist during a Endoscopic Retrograde Cholangiopancreatography (ERCP) by assessing the basal sphincter pressure using a manometry catheter, also called a motility catheter. The catheter, which is designed to be situated within sphincter of Oddi, includes one or more distal ports that infuse saline against the walls of the sphincter. The pressure exerted by the muscles of the sphincter is measured and used to assess the tone of sphincter and help determine if SOD is present. One example of a SOD manometry catheter is the Lehman Sphincter of Oddi Manometry Catheter (Wilson-Cook Medical, Winston-Salem, N.C.). It is a three-lumen catheter with two manometry ports located about the distal end. The two ports communicate with two luer connectors which attach to transducer of a separate recording system for measuring the resistance applied by the sphincter to the saline being infused through the ports by an infusion pump which also has been attached to the manometry catheter. After flushing the wire guide lumen, the catheter is fed over the wire guide pre-positioned in the bile duct and then into the endoscope accessory channel. The manometry catheter is then maneuvered under endoscopy into the cannulated SOD and a series of pressure readings are made to access the condition of the sphincter. A basal tone of more than 40 mm Hg is an indicator that the sphincter cannot effectively regulate bile flow and/or pass smaller stones into the duodenum.
Typically, a hypertensive SOD is treated by ablation of the sphincter muscles, a procedure called a sphincterotomy, using a second, specialized catheter known as a sphincterotome. A biliary sphincterotome is an endoscopic catheter that includes a wire, typically braided or monofilament stainless steel, that extends from the distal end of the catheter or exits the catheter for only a portion of its length. The wire is connected to a electrosurgical generator that delivers current that allows the wire to ablate tissue with which it comes into contact. A sphincterotomy is often selected as the desired treatment after a manometry catheter has been used to establish that the sphincter is hypertensive. The manometry catheter must first be removed from the scope accessory channel, which is only large enough to accommodate a single device. The sphincterotome is then fed over the wire guide, if used, which remains in the bile duct. After the physician has maneuvered the sphincterotome into the papilla, current is applied to the cutting wire and the sphincter muscles are ablated, thereby creating a larger opening for the drainage of bile and/or passage of stones.
Depending on the symptoms displayed by the patients, the likelihood of a sphincterotomy being performed can be rather high, once the physician has made the decision that the basal tone of the sphincter should be measured via a manometry catheter. Therefore, in a large number of patients, a sphincterotome will be required to be introduced through the endoscope to the site to replace the manometry catheter. What is needed is a way to more efficiently treat SOD by eliminating the need to replace devices once a confirmation of sphincter hypertension has been made. Ideally, such a solution should reduce the overall duration of the combined diagnostic and therapeutic procedures while including the full ability to perform each. Furthermore, such a device should reduce the risks associated with introducing a second device and be cost effective over a reasonable number of procedures, taking into account that there is a significant percentage of SOD studies that do not result in a sphincterotomy being performed.